Callahan

Petitioner Henry Callahan contends that all of his psychiatric disability is related to his industrial injury of August 21, 1969, and that the Workers’ Compensation Appeals Board (Board) erred in apportioning 50 percent of his psychiatric disability to preexisting nonindustrial causes. Respondent McDonnell Douglas Corporation (McDonnell), which was Callahan’s employer at the time of the industrial injury of August 21, 1969, and its workers’ compensation insurance carrier, Industrial Indemnity Company (Industrial Indemnity), argue in rebuttal that the Board correctly apportioned Callahan’s disability in that different rules of apportionment should apply to “psychiatric” as opposed to “physical” injuries. For the reasons stated below, we annul the Board’s finding of apportionment and remand the question for further evaluation.

I

Callahan, while employed on August 21, 1969, by McDonnell, sustained injury arising out of and occurring in the course of his employment to his head and neck. The injury also resulted in psychiatric disability.

The workers’ compensation judge initially found that Callahan’s industrial injury of August 21, 1969, did not result in any psychiatric…